The change of molecular dipole moment induced by photon absorption is key to interpret the measured optical spectra. Except for compact molecules, time-dependent density functional theory (TD-DFT) remains the only theory allowing to quickly predict excited-state dipoles (μ), albeit with a strong dependency on the selected exchange-correlation functional. This Letter presents the first assessment of the performances of the many-body Green's function Bethe-Salpeter equation (BSE) formalism for the evaluation of the μ. We explore increasingly long push-pull oligomers as they present an excited-state nature evolving with system size. This work shows that BSE's μ do present the same evolution with oligomeric length as their CC2 and CCSD counterparts, with a dependency on the starting exchange-correlation functional that is strongly decreased as compared to TD-DFT. This Letter demonstrates that BSE is a valuable alternative to TD-DFT for properties related to the excited-state density and not only for transition energies and oscillator strengths.
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http://dx.doi.org/10.1021/acs.jpclett.3c00699 | DOI Listing |
J Chem Phys
January 2025
Volgograd State University, University Avenue 100, Volgograd 400062, Russia.
The first excited state of conjugated donor-acceptor molecules of C3 symmetry (octupolar molecules) is doubly degenerate. Such a doublet is known to be isomorphic to a spin 1/2. It is shown that a large electric dipole moment is associated with this spin.
View Article and Find Full Text PDFLight Sci Appl
January 2025
Center for Nanoscience and Technology, Istituto Italiano di Tecnologia, Milano, 20134, Italy.
We introduce a family of membrane-targeted azobenzenes (MTs) with a push-pull character as a new tool for cell stimulation. These molecules are water soluble and spontaneously partition in the cell membrane. Upon light irradiation, they isomerize from trans to cis, changing the local charge distribution and thus stimulating the cell response.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Max Planck Institute for the Structure and Dynamics of Matter and Center for Free-Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg, Germany.
In this work, we theoretically explore whether a parity-violating/chiral light-matter interaction is required to capture all relevant aspects of chiral polaritonics or if a parity-conserving/achiral theory is sufficient (e.g., long-wavelength/dipole approximation).
View Article and Find Full Text PDFChem Sci
January 2025
Faculty of Chemistry, Institute of Theoretical Chemistry, Universität Wien A-1090 Vienna Austria
Recent developments in quantum computing are highly promising, particularly in the realm of quantum chemistry. Due to the noisy nature of currently available quantum hardware, hybrid quantum-classical algorithms have emerged as a reliable option for near-term simulations. Mixed quantum-classical dynamics methods effectively capture nonadiabatic effects by integrating classical nuclear dynamics with quantum chemical computations of the electronic properties.
View Article and Find Full Text PDFChem Sci
January 2025
Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata Mohanpur West Bengal India-741246
Red emission in crystals has been observed with an ultra-small-single-benzenic -fluorophore () with a molecular weight (MW) of only 197 Da, bettering the literature report of fluorophores with the lowest MW = 252 Da. Supramolecular extensive hydrogen-bonding and J-aggregate type centrosymmetric discrete-dimers or a 1D chain of s led to red emission ( = 610-636 nm) in crystals. Unlike in the solution phase showing one absorption band, in thin films and in crystals the transition from the S state to both the S state and S state becomes feasible.
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